Ultrasound treatment apparatus

ABSTRACT

An ultrasound treatment apparatus includes an ultrasound source for generating treatment ultrasound which is focused, a driving circuit for driving the ultrasound source to generate treatment ultrasound from the ultrasound source, and a controller for controlling to make the driving circuit drive the ultrasound source under an irradiation condition in which an optimization index obtained by the product of the focus intensity (W/cm 2 ), the irradiation period (sec), and the frequency (MHz) all of the treatment ultrasound falls within an appropriate range from 6,000 (inclusive) to 40,000 (inclusive).

BACKGROUND OF THE INVENTION

[0001] The present invention relates to an ultrasound treatmentapparatus for necrosing a tumor such as a tumor by focusing ultrasoundon the tumor.

[0002] A great deal of attention has recently been given to MIT(Minimally Invasive Treatment). For example, a ESWL (ExtracorporealShock Wave Lighotriptor (Lighoripsy)) is available, which destroys acalculus by extracorporeally irradiating the calculus with energyinstead of a surgical operation. Such energy is generated by a(submerged) discharge type, electromagnetic (induction) type,small-explosion type, piezoelectric type, and the like. Thepiezoelectric type, in particular, has the following advantages. Forexample, energy can be focused to a pinpoint spot, no expendablecomponent is required, energy control is easy, and focal positioncontrol is easy (Jpn. Pat. Appln. KOKAI Publication No. 60-145131 andU.S. Pat. No. 4,526,168).

[0003] In recent years, a less invasive treatment method which focuseson QOL (Quality Of Life) is receiving a great deal of attention. Themainstream of treatment methods for malignant tumors, i.e., cancers, isconstituted by surgery, radiotherapy, and chemotherapy. These treatmentmethods often accompany the hypofunction of an internal organ and achange in the form of the organ. For this reason, even if the patientslife is prolonged, the patient must bear a large burden. QOL is theconcept that tries to minimize the burden on the patient after treatmentby reducing invasion due to the treatment.

[0004] One of cancer treatment techniques capable of realizing QOL isthermotherapy, and more specifically, hyperthermia that uses thedifference in heat sensitivity between cancer tissue and normal tissue.In hyperthermia, the tumor (target) temperature is kept at about 42.5°,which is the necrosis temperature of a cancer cell. Since the necrosistemperature of normal tissue is slightly higher than that of cancertissue, the normal tissue is not necrosed.

[0005] Heating is performed by various method. If heating is performedby using electromagnetic waves such as microwaves, the electromagneticwaves may be deflected by the electrical characteristics of a livingbody and may necrose normal tissue around the tumor. In addition, theelectromagnetic field can hardly reach the deep tumorous region or deeplying region within a body which depth is more than 5 cm from the skin.As a means for solving this problem, a method of inserting amicrowave/RF wave antenna into a portion near a tumor has received agreat of attention (Isoda et al., J. Microwave Surgery).

[0006] Advantageous characteristics of ultrasound are that no surgicaloperation is required, energy can be focused to a high degree, energycontrol is easy, and energy can reach relatively deep (Jpn. Pat. Appln.KOKAI Publication No. 61-139551). Recently, a treatment method ofnecrosing a tumor accompanying thermal coagulation by instantaneouslyheating the tumor to 80° C. or more by using very strong ultrasoundwhose ultrasound intensity reaches several hundred to several thousandW/cm² at the focus has been developed (G. Vallancien et al.: ProgressinUrol, 1991, 1, 84-88, U.S. Pat. No. 5,150,711).

[0007] In this treatment method, since ultrasound is focused to a veryhigh degree to form a very small spot, the focus of ultrasound must bemoved to entirely treat a large tumor. For this reason, it is requiredto improve the positioning precision of the focus with respect to thetumor. To improve the positioning precision, the present inventors havedeveloped a technique of imaging the body temperature distribution byusing an MRI (Magnetic Resonance Imaging Apparatus) on the basis of thetemperature dependency of chemical shift (Jpn. Pat. Appln. KOKAIPublication No. 5-253192). In addition, a technique of imaging theintensity distribution of treatment ultrasound by receiving the echoesof the treatment ultrasound generated by a treatment ultrasound sourcewith an imaging probe has been developed (U.S. Pat. Nos. 1,851,304,1,821,772, and 1,765,452). An improvement in positioning precision canbe attained by using various techniques, as described above.

[0008] In addition to an improvement in positioning precision, anotherchallenge for ultrasound treatment is optimization of the amount ofenergy injected (ultrasound intensity×irradiation period). According tothe experiment conducted by the present inventors, injection ofexcessive energy causes destruction of a tissue cell beyond thermaldegeneration. In a thermal degenerate state, the tissue cell isnecrosed, but it maintains its form. If, however, the tissue cell isdestroyed, its original form changes. For this reason, a tumor orneighboring blood vessels may be damaged. As one method of solving thisproblem, the present inventors have proposed a phase difference drivingmethod of decreasing the ultrasound intensity (focus intensity) at afocus and widening the acoustic field (Japanese Patent Application Nos.10-278684 and 10-279088). However, optimization rules for focusintensity and irradiation periods could not be established.

[0009] As is known, ultrasound energy is absorbed at an acousticimpedance boundary. For this reason, a portion exhibiting a largedifference in acoustic impedance, e.g., the body surface of a patient,is unintentionally heated, and may be burnt. There are no appropriatecountermeasures against such situations.

[0010] Often, a portion near a focus is scanned with an imagingultrasound probe to acquire B-mode images near the focus so as to checkthe progress of treatment while strong treatment ultrasound isirradiated. Typically, the frequency of the strong treatment ultrasoundis set to 1.6 MHz, whereas the driving frequency of the imagingultrasound probe is set to 3.7 to 5.0 MHz. The main components of strongtreatment ultrasound echoes are not received by the vibrator of theimaging ultrasound probe. However, harmonic components of the echoes arereceived as noise by the vibrator of the imaging ultrasound probe. Sincethe noise is much higher in intensity than the imaging ultrasound, theresultant B-mode image becomes almost white. This makes it difficult toobserve the tumor.

[0011] As a means for solving this problem, Jpn. Pat. Appln. KOKAIPublication Nos. 60-241436, 60-241436, and 10-216145 disclose atechnique of stopping irradiation of treatment ultrasound atpredetermined intervals, and executing scanning operation using imagingultrasound only during the stop periods, thereby acquiring B-mode imageswithout noise.

[0012] On the other hand, the operator can use almost white B-modeimages to visually check whether treatment ultrasound is reallyirradiated. If, however, scanning operation using imaging ultrasound isexecuted only during stop periods of treatment ultrasound, the operatorcannot visually check whether the treatment ultrasound is reallyirradiated, although B-mode images without noise can be acquired.

[0013] In the arrangements disclosed in Jpn. Pat. Appln. KOKAIPublication Nos. 60-241436 and 10-216145, a control signal must bedirectly input from an ultrasound treatment apparatus to an ultrasoundtransmitting/receiving section of an ultrasound image diagnosticapparatus or an output must be directly extracted from the ultrasoundtreatment apparatus. For this reason, if at least a conventionalultrasound treatment apparatus is to be used, the ultrasoundtransmitting/receiving section inside the apparatus must be modified, orthe ultrasound treatment apparatus and the ultrasound image diagnosticapparatus must be integrated. When image information is to be loadedfrom various image diagnostic apparatuses, e.g., an X-ray imagediagnostic apparatus, X-ray CT apparatus, and MRI apparatus, other thanan ultrasound treatment apparatus, it is difficult to make modificationsfor loading of image information with respect to various imagediagnostic apparatuses to be combined.

BRIEF SUMMARY OF THE INVENTION

[0014] It is an object of the present invention to perform safe,appropriate medical treatment by using an ultrasound treatmentapparatus.

[0015] According to the present invention, medical treatment isperformed under an irradiation condition in which an optimization indexobtained by the product of the focus intensity (W/cm²) of treatmentultrasound, the irradiation period (sec) of the treatment ultrasound,and the frequency (MHz) of the treatment ultrasound falls within theappropriate range of 6,000 (inclusive) to 40,000 (inclusive).

[0016] According to the present invention, since an irradiationcondition is determined on the basis of the focus intensity of treatmentultrasound and the ultrasound intensity in a hyper Echoic regionincluding the body surface of a patient, both optimization of treatmentfor a tumor and a reduction in damage to the body surface and the likecan be attained.

[0017] According to the present invention, treatment ultrasound isalternately generated and stopped, and scanning with imaging ultrasoundis continuously repeated. B-mode image data sequentially obtained byrepetitive scanning are displayed as moving images in real time. B-modeimage data corresponding to stop periods of treatment ultrasound arepicked up from the B-mode image data sequentially obtained by thisrepetitive scanning. These picked-up B-mode image data are displayed asskip images. Since a B-mode image during a stop period of treatmentultrasound has an appropriate intensity, the tissue form can beobserved. In contrast to this, a B-mode image during a generation periodof treatment ultrasound has an excessively high intensity, and hencelooks completely white. This makes it impossible to see any tissue form,but allows the operator to determine that treatment ultrasound is indeedirradiated.

[0018] In the present invention, treatment ultrasound is alternatelygenerated and stopped, and scanning with imaging ultrasound isintermittently executed in synchronism with stop periods of thetreatment ultrasound. Some of scanning periods overlap the generationperiods of treatment ultrasound. Therefore, a B-mode image partly lookscompletely white to hinder the operator from seeing any tissue form.This, however, allows the operator to determine that treatmentultrasound is actually irradiated. In contrast to this, the remainingpart of the B-mode image is obtained during a stop period of thetreatment ultrasound, and hence is displayed with an appropriateintensity. This allows the operator to observe the tissue form.

[0019] According to the present invention, treatment ultrasound isalternately generated and stopped, and scanning with imaging ultrasoundis continuously repeated. B-mode image data corresponding to scanningperiods which partly overlap stop periods of treatment ultrasound arepicked up from the sequentially obtained B-mode image data. Part of aB-mode image therefore looks completely white, and hence does not allowthe operator to see any tissue form. This, however, allows the operatorto determine that treatment ultrasound is actually irradiated. Theremaining part of the B-mode image is obtained during a stop period ofthe treatment ultrasound, and hence is displayed with an appropriateintensity. This allows the operator to observe the tissue form.

[0020] The treatment apparatus of the present invention continuously andexternally inputs B-mode image data associated with a cross-sectionincluding the focus of treatment ultrasound, picks up B-mode image datacorresponding to stop periods of the treatment ultrasound, and displaysthe data as skip images.

[0021] The treatment apparatus of the present invention continuously andexternally inputs B-mode image data associated with a cross-sectionincluding the focus of treatment ultrasound, picks up the intensity ofthe focus from the B-mode image data, and displays the intensity as achange over time. The operator can monitor the progress of treatmentfrom this change in intensity over time.

[0022] Additional objects and advantages of the invention will be setforth in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention may be realized and obtained bymeans of the instrumentalities and combinations particularly pointed outhereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0023] The accompanying drawings, which are incorporated in andconstitute a part of the specification, illustrate presently preferredembodiments of the invention, and together with the general descriptiongiven above and the detailed description of the preferred embodimentsgiven below, serve to explain the principles of the invention.

[0024]FIG. 1 is a block diagram showing the arrangement of an ultrasoundtreatment apparatus according to the first embodiment of the presentinvention;

[0025]FIG. 2 is a graph showing the appropriate range of an irradiationcondition according to the first embodiment;

[0026]FIG. 3A is a view showing an example of display of an irradiationcondition in the first embodiment;

[0027]FIG. 3B is a graph showing the details of the display of theirradiation condition in FIG. 3A;

[0028]FIG. 4 is a block diagram showing the arrangement of an ultrasoundtreatment apparatus according to the second embodiment of the presentinvention;

[0029]FIG. 5 is a flow chart roughly showing a procedure for setting anirradiation condition in the second embodiment;

[0030]FIG. 6A is a graph showing the relationship between the state of acell and the ultrasound intensity and irradiation time at a focus;

[0031]FIG. 6B is a graph showing the relationship between the state of acell and the ultrasound intensity and irradiation time on the bodysurface of a patient;

[0032]FIG. 7 is a flow chart showing the details of a procedure forsetting an irradiation condition in the second embodiment;

[0033]FIG. 8A is a view showing an example of display of an irradiationcondition in the second embodiment;

[0034]FIG. 8B is a graph showing the details of the display of theirradiation condition in FIG. 8A;

[0035]FIG. 8C is a graph showing the details of another example of thedisplay of the irradiation condition in FIG. 8A;

[0036]FIG. 9 is a flow chart showing a procedure for completingirradiation in the second embodiment;

[0037]FIG. 10 is a block diagram showing the arrangement of anappropriate range setting circuit for ultrasound intensities in thesecond embodiment;

[0038]FIG. 11 is a block diagram showing the arrangement of anultrasound treatment apparatus according to the third embodiment of thepresent invention;

[0039]FIG. 12 is a block diagram showing the arrangement of anultrasound driving circuit 204 in FIG. 11;

[0040]FIG. 13 is a timing chart showing scanning operation and stillimage capturing operation corresponding to generation of treatmentultrasound in the dual mode in the third embodiment;

[0041]FIG. 14 is a view showing a dual display window corresponding tothe operation in FIG. 13;

[0042]FIG. 15 is a block diagram showing another example of thearrangement of the ultrasound driving circuit 204 in FIG. 11;

[0043]FIG. 16 is a timing chart showing scanning operation correspondingto generation of treatment ultrasound in the single mode in the thirdembodiment;

[0044]FIG. 17A is a view showing a single display window correspondingto operation “A” in FIG. 16;

[0045]FIG. 17B is a view showing a single display window correspondingto operation “B” in FIG. 16;

[0046]FIG. 17C is a view showing a single display window correspondingto operation “C” in FIG. 16;

[0047]FIG. 18 is a timing chart showing another scanning operationcorresponding to generation of treatment ultrasound in the signal modein the third embodiment;

[0048]FIG. 19 is a block diagram showing a modification of the thirdembodiment;

[0049]FIG. 20A is a view showing the state of a tumor before irradiationof treatment ultrasound in the third embodiment;

[0050]FIG. 20B is a view showing the state of the tumor afterirradiation of treatment ultrasound;

[0051]FIG. 21 is a block diagram showing the arrangement of anultrasound treatment apparatus according to the fourth embodiment towhich an ultrasound imaging function is externally added;

[0052]FIG. 22 is a timing chart showing the operation of the fourthembodiment;

[0053]FIGS. 23A and 23B are views showing an example of display in thefourth embodiment; and

[0054]FIG. 24 is a view showing another example of display in the fourthembodiment.

DETAILED DESCRIPTION OF THE INVENTION

[0055] Preferred embodiments of the present invention will be describedin detail below with reference to the views of the accompanying drawing.

[0056] (First Embodiment)

[0057]FIG. 1 shows the arrangement of an ultrasound treatment apparatusaccording to the first embodiment. An applicator 1 has a treatmentultrasound source 2 for generating strong treatment ultrasound. Thetreatment ultrasound source 2 has a plurality of piezoelectric elementseach having upper and lower electrodes. The plurality of piezoelectricelements are systematically arranged toward a focus.

[0058] A hole is formed near the center of the treatment ultrasoundsource 2, and an imaging ultrasound probe (inner probe) 15 for acquiringa B-mode image (B-mode image (form image)) associated with across-section including the focus is inserted in this hole. An operatorpositions a focus 8 on a tumor 7 and checks the progress of treatmentwhile referring to the B-mode image acquired by an ultrasound imagingapparatus 16 through the imaging ultrasound probe 15 and including atumor (tumor) 7 displayed on a CRT 18.

[0059] Since a mark indicating the position of the focus 8 of thetreatment ultrasound source 2 is synthesized with this B-mode image by adigital scan converter 17, the operator can relatively easily positionthe applicator 1 by manually moving it to align the focus mark with thetumor 7 of a patient 3. The operator can finally confirm on the B-modeimage obtained by the ultrasound imaging apparatus 16 that the focus 8is aligned with the tumor 7.

[0060] With recent great reductions in the size and weight of theapplicator 1, a hand-held type (portable) applicator like the one shownin FIG. 1 can be implemented. However, the applicator 1 may be supportedby a conventional support mechanism with a balancer function to befreely moved or may be motorized.

[0061] When the applicator 1 is to be moved, the distance from a tumorsurface 6 to the focus 8 must be changed by adjusting the amount ofcoupling liquid 4 in the applicator 1 using a water circuit (pump) 20.In general, in this liquid amount adjustment, the operator determinesthe amount of liquid by operating a console panel 10 by himself/herself.If the tumor depth from the tumor surface 6 to the tumor 7 is known,liquid amount adjustment or the like may be automatically controlled inaccordance with a command from a system controller 9 by designating thetumor depth. Adjustment of this tumor depth may be performed byattaching/detaching a coupler, acoustic lens, or the like so as tochange the depth of focus instead of adjusting the amount of couplingliquid. If the focus 8 can be electronically scanned by phase control,the above tumor depth adjustment may be performed by changing thedriving phases between the piezoelectric elements.

[0062] The coupling liquid 4 is sealed with a coupling film 5 on theultrasound irradiation side of the treatment ultrasound source 2 toguide the treatment ultrasound generated by the treatment ultrasoundsource 2 to the body surface of the patient 3 with little attenuation.In treatment, the coupling film 5 is brought into contact with the tumorsurface 6 of the patient 3 through ultrasound jelly (or the like).

[0063] When the operator operates the console panel 10 or an irradiationstart switch mounted on the applicator 1 upon positioning the applicator1 while referring to a B-mode image, the system controller 9 controls awave form generating circuit 12 and driver 13. With this operation, thewave form signal generated by the wave form generating circuit 12 isamplified by the driver 13 and supplied to each piezoelectric element ofthe treatment ultrasound source 2 through an impedance matching circuit14. As a consequence, treatment ultrasound is irradiated upon mechanicalvibrations of the piezoelectric elements.

[0064] A type of optimizing the irradiation condition, which is one ofthe important features of this embodiment, will be described next. Thisirradiation condition includes an irradiation period t (sec) and drivingelectric power P (W) supplied from the driver 13 to each piezoelectricelement per unit time. The driving electric power P (W) is determined byan ultrasound intensity (focus intensity) I_(F) (W/cm²) at the positionof the focus 8, an ultrasound attenuation coefficient in the livingbody, and the like. Information required for the system controller 9 tocalculate and determine this optimal irradiation condition is stored ina memory 11 in advance.

[0065] This required information includes a resonance frequency fintrinsic to a piezoelectric element 102 and a parameter representing acorrelation between the driving electric power intrinsic to thetreatment ultrasound source 2 and the focus intensity (a correlationbetween the unit driving electric power in water and the focus intensityat a unit depth (1 cm).

[0066] The required information further includes an upper limit valueE_(MAX) of optimization indexes (frequency/energy densities) withinwhich over-irradiation (cell destruction) does not occur and a lowerlimit value E_(MIN) within which under-irradiation (non-thermaldegeneration) does not occur. These value are intrinsic to an internalorgan. If, therefore, the irradiation condition is set such that theoptimization index falls within the range from the lower limit valueE_(MIN) to the upper limit value E_(MAX) (appropriate range), the tumordegenerates without causing any cell destruction in the tumor. That is,thermal degeneration of the tumor can be properly caused.

[0067] The required information also includes an upper limit valueI_(FMAX) of the focus intensity I_(F) and an ultrasound attenuationcoefficient a of each internal organ. These pieces of requiredinformation are stored in a memory 11 in correspondence with therespective internal organs.

[0068] The upper limit value E_(MAX) and lower limit value E_(MIN) of afrequency/energy density and the upper limit value I_(FMAX) of the focusintensity I_(F) are determined for each internal organ experimentally,empirically, and by simulation. For example, for the liver, the. upperlimit value E_(MAX) of the frequency/energy density is determined to be40,000; the lower limit value E_(MIN) of the frequency/energy density,6,000; and the upper limit value I_(FMAX) Of the focus intensity I_(F),2,000.

[0069] The above frequency/energy density is an index (optimizationindex) newly introduced by the present invention. This value is given bythe product of the focus intensity I_(F), irradiation period (sec), anddriving frequency (MHz). This frequency/energy density exhibits a veryhigh correlation with the thermal degeneration state of a tumor. Aproper irradiation condition under which desired thermal degenerationcan be caused in focus tissue and no cell destruction occurs insurrounding tissue can be effectively determined on the basis of thisfrequency/energy density.

[0070] A procedure by which the system controller 9 determines anappropriate irradiation condition (irradiation period t and drivingelectric power P) will be described next. This determination procedurecan be divided into two stages, i.e., the determination stage for thefocus intensity I_(F) and irradiation period t and the determinationstage for the driving electric power P. The determination stage for thefocus intensity I_(F) and irradiation period t will be described first.Of the focus intensity I_(F) and irradiation period t, the irradiationperiod t is generally determined by the operator in many cases. For thisreason, the procedure for determining the focus intensity I_(F) will bedescribed first.

[0071] When the operator inputs the irradiation period t and informationindicating a target internal organ through the console panel 10, theupper limit value E_(MAX) of the frequency/energy density linked to thetarget internal organ, the lower limit value E_(MIN) of thefrequency/energy density linked to the target internal organ, and theupper limit value I_(FMAX) of the focus intensity I_(F) linked to thetarget internal organ are loaded from the memory 11 into the systemcontroller 9, together with the driving frequency f intrinsic to theapplicator 1.

[0072] The system controller 9 determines the appropriate range of thefocus intensity I_(F) so as to satisfy

E _(MIN)≦frequency·energy density≦E _(MAX)

[0073] That is,

E _(MIN)≦focus intensity I _(F) (W/cm²)×irradiation period t(second)×driving frequency f (MHz)≦E _(MAX)  (1)

[0074] and the upper limit value I_(FMAX) of the focus intensity I_(F).Proper medical treatment can be performed within the determinedappropriate range of the focus intensity I_(F). In practice, asubstantially median value in the appropriate range is determined as theappropriate focus intensity I_(F). FIG. 2 shows changes in focusintensity I within the appropriate range over the irradiation period t.

[0075] Note that the operator may determine the focus intensity I_(F) inadvance, and the system controller 9 may determine the appropriateirradiation period t. In this case as well, the appropriate range of theirradiation period t is determined according to relation (1), and themedian value in the range is determined as the appropriate irradiationperiod t. In general, for example, in the case of the liver, the focusintensity at the focus 8 is set to 1,000 W/cm² (≦I_(FMAX)=2,000), andthe driving frequency is assumed to be 1.6 MHz. According to theexperiment conducted by the present applicants, in the case of theliver, the upper limit value E_(MAX) of the frequency/energy density was40,000, and the lower limit value E_(MIN) of the frequency/energydensity was 6,000.

[0076] Under this assumption, it suffices if the irradiation period tsatisfies

6,000≦1,000 (W/cm²)×irradiation period (second)×1.6 (MHz)≦40,000  (2)

[0077] Therefore, proper medical treatment can be performed within therange of about 4 sec to about 25 sec. In practice, in consideration ofupper and lower margins, a substantially median value in this range,i.e., about 15 sec, is provided as an appropriate irradiation period.This value is in good agreement with the result obtained by the testsconducted on animals by the present inventors.

[0078] A method of determining an appropriate value of driving electricpower to be supplied from the driver 13 to each piezoelectric elementwill be described next. Since this driving electric power can beoptimized by using the conventional method without any change, thismethod will be briefly described below by taking the liver as anexample. In the case of the liver, the ultrasound attenuationcoefficient α is about 0.7 dB/MHz/cm. The driving frequency ofultrasound is set to 1.6 MHz as in the above case.

[0079] The focus intensity is attenuated, for every depth of 1 cm, to

10 (−0.7×1.6 MHz−(1 cm/10)=0.773  (3)

[0080] Since the focus intensity I must be kept constant for everydepth, the driving electric power must be increased by about 1.3 timesfor every depth of 1 cm. According to this estimation, assuming that theultrasound intensity at a depth of 1 cm with a driving electric power of2,000 W becomes 1,000 W/cm² as a correlation parameter between the unitdriving electric power P in water and the ultrasound intensity at a unitdepth (1 cm), in order to obtain an appropriate ultrasound intensity ata depth of 5 cm, the driving electric power given by

2000/10^((−α×1.6) MHz×(5−1) cm/10)=560 W  (4)

[0081] is determined as an appropriate value.

[0082] As described above, in the case of the liver, an irradiationperiod of 15 sec and a driving electric power of 560 W are calculated asappropriate values for proper medical treatment at a depth of focus of 5cm. The system controller 9 performs such calculations to irradiateultrasound with values corresponding to a treatment target and thecharacteristics of the target. This makes it possible to perform safe,reliable medical treatment.

[0083] Although the operator may input a numerical value as a tumordepth through the console panel 10, semiautomatic control may beperformed to make the system controller 9 calculate the distance betweenthe focus and the contact surface between the body surface and thecoupling film as a tumor depth when the operator designates the tumor(tumor) 7, together with the contact surface, on a B-mode image.Furthermore, full-automatic control may be performed to make the systemcontroller 9 automatically extract a body surface and tumor (tumor) froma B-mode image by image processing and calculate the distance betweenthe body surface and the tumor as a tumor depth. This calculation can beautomated by the following method. The distance from the treatmentultrasound source 2 to the body surface can be approximated from theamount of coupling liquid 4 injected. In the applicator 1 of the type inwhich the distance (focal length) from the treatment ultrasound source 2to the focus is fixed, therefore, the tumor depth can be calculated bysubtracting the distance from the treatment ultrasound source 2 to thebody surface from the focal length.

[0084] As described above, at a depth of focus of 5 cm, an irradiationperiod of 15 sec and a driving electric power of 560 W are calculated asappropriate values for proper medical treatment. The system controller 9performs such calculations to irradiate ultrasound with valuescorresponding to a treatment target and the characteristics of thetarget, thus realizing safe, reliable medical treatment.

[0085] In setting such a treatment condition, the irradiation conditionset is graphically displayed, as shown in FIGS. 3A and 3B. The operatorcan therefore easily set or adjust (correct) the irradiation conditionby manual operation.

[0086] As described above, according to this embodiment, the followingeffects can be obtained. The product of an ultrasound intensity (focusintensity) (W/cm²), irradiation period (sec), and driving frequency(MHz) at the focal position in the living body, i.e., thefrequency/energy density, has a high correlation with the degenerationstate of a tumor. For this reason, a proper irradiation condition underwhich desired thermal degeneration can be caused in focus tissue and nodamage is caused to the surrounding tissue can be finely determined onthe basis of the frequency/energy density. This makes it possible tosufficiently treat the tumor without producing any side effect due to anexcessive focus intensity, thus allowing safe, efficient irradiationtreatment.

[0087] In addition, the values (I_(MAX), E_(MAX) , E_(MIN) ) are notinfluenced much by the size of the focus 8. This embodiment cantherefore properly cope with a case wherein irradiation treatment isperformed while the focus size is changed, as disclosed in JapanesePatent Application Nos. 10-278684 and 10-279088 and Japanese Patent Nos.2036277 and 2576427. In this case, if changes in the maximum intensityof ultrasound with changes in focus size are stored in the memory 11 orthe like in advance, the irradiation intensity can be set by reading outan intensity value corresponding to the driving method used.

[0088] Assume that the system controller 9 monitors irradiation oftreatment ultrasound, and detects that at least one of the followingcases has occurred: a case wherein the frequency/energy density at thefocal position falls outside the range of the upper and lower limitvalues of frequency/energy densities selectively read out from thememory 11; and a case wherein the ultrasound intensity at the focalposition exceeds the upper limit value of ultrasound intensitiesselectively read out from the memory 11. In this case, a control signal(inhibit signal) for urgent stop may be sent to the driver 13 tourgently stop irradiation of treatment ultrasound or a specific sound orbuzzer sound indicating the occurrence of the above event may begenerated as a warning (alarming) through a speaker 19. Alternatively, agraphic signal may be sent to the CRT 18 through the digital scanconverter 17 to display a specific message indicating the occurrence ofthe above event on the screen. One, two, or all of these operations,i.e., urgently stopping irradiation, generating a warning, anddisplaying a message, may be executed.

[0089] In the above description, the upper limit values and the like offrequency/energy densities are linked with internal organs. However, theirradiation condition may be further optimized by determining the upperand lower limit values of frequency/energy densities and the upper limitvalue of focus intensities more finely in accordance with eachindividual internal organs and the progress of a symptom and linkingthem with each other.

[0090] According to the above description, information such as the upperlimit value of frequency/energy densities which is required to allow thesystem controller 9 to determine an appropriate irradiation conditionare stored in the memory 11 in advance, and the system controller 9calculates appropriate values on the basis of the information.Appropriate irradiation conditions calculated by the above determinationmethod in advance may be stored in the memory 11, and an appropriateirradiation condition may be read out in accordance with an inputcondition such as information indicating an internal organ.

[0091] In addition, the attenuation characteristics of a path and otherultrasound characteristics may be measured or estimated by a means foracquiring ultrasound image and other data, and the condition may be seton the basis of the characteristic values.

[0092] The irradiation condition set in the above manner is a conditionin a case wherein the focal position is fixed, and ultrasound iscontinuously irradiated. However, by sequentially updating theirradiation condition, this embodiment can be applied to a case whereinmedical treatment is performed while the focus is moved in a wide range.When ultrasound is intermittently irradiated at multiple points insteadof being continuously irradiated, since energy has been partly conductedby preceding irradiation owing to thermal conduction and the like,treatment ultrasound can be driven with the value obtained bysubtracting the value of the conducted energy (energy density per unitvolume) from the total energy.

[0093] Only the ultrasound treatment apparatus has been described above.However, the present invention can be applied to other types oftreatment methods, e.g., a method of using microwaves to heat/treat atumor by using energy absorption in tissue.

[0094] According to the present invention, the following effect can beobtained. The product of an ultrasound intensity (W/cm²) at a focalposition in the living body, irradiation period (sec), and drivingfrequency (MHz) exhibits a high correlation with thermal degeneration ofthe tumor. For this reason, an irradiation condition under which desiredthermal degeneration can be caused in focus tissue and no damage iscaused to the surrounding tissue can be finely determined. This makes itpossible to sufficiently treat the tumor without producing any sideeffect due to an excessive focus intensity, thus allowing safe,efficient irradiation treatment.

[0095] (Second Embodiment)

[0096] As shown in FIG. 4, an applicator 101 is comprised of a treatmentultrasound source 102 which is made up of a plurality of piezoelectricelements and generates strong treatment ultrasound, coupling liquid 104for guiding strong treatment ultrasound to a patient 103, coupling film105, and imaging ultrasound probe 115 for acquiring a B-mode imageinside the body.

[0097] In medical treatment, the patient 103 is instructed to lie on abed and fixed at a predetermined position. The applicator 101 is placedon the body surface of the patient 103, and the coupling film 105 isbrought into contact with a body surface 106 covered with an ultrasoundjelly or the like. In positioning the applicator 101, a B-mode imageincluding a tumor (tumor) 107 is reconstructed by an ultrasound imagingapparatus 116 on the basis of a reflected wave signal from the patient103 which is acquired by the imaging ultrasound probe 115 inserted inthe center of the applicator 101, and the position of an ultrasoundfocus 108 of the treatment ultrasound source 102 is displayed on a CRT118 through a DSC 117 so as to be superimposed on the reconstructedimage.

[0098] A command is output to a stage controller 119 in accordance witha signal from a system controller 109 to align the focal position onthis image with the tumor (tumor) 107 inside the patient 103. The stagecontroller 119 then controls a stage 120 and arm 121 to move theapplicator 101 in accordance with the instruction, thereby positioningthe applicator 101.

[0099] In this embodiment, as shown in FIG. 5, after positioning iscompleted, the operator designates, on a console panel 110, a hyperEchoic region represented by the body surface of a patient whichexhibits a large acoustic impedance difference (step S1). This hyperEchoic region is a region which noticeably generates heat uponirradiation of treatment ultrasound; This region includes the boundarybetween internal organs, the body surface of the patient, and the like.In this case, a case of a body surface as a hyper Echoic region will bedescribed. In this embodiment, an irradiation condition (drivingelectric power, irradiation period, and irradiation interval) underwhich degeneration of a tumor is appropriately caused, and damage to thebody surface (hyper Echoic region) is minimized is read out from amemory 111 (step S2). In accordance with a command from the systemcontroller 109, movement/irradiation control on the applicator 101 isperformed (step S3).

[0100] In this irradiation operation, a wave form generating circuit 112generates a wave form signal in accordance with the irradiationcondition stored in the memory 111. This wave form signal is amplifiedby an RF amplifier 113 to excite the piezoelectric elements of thetreatment ultrasound source 102 through a matching circuit 114.

[0101] In this embodiment, the operator may manually designate a hyperEchoic region between the treatment ultrasound source 102 and the focusby using the console panel 110, or a region in which the intensity of aB-mode image exceeds a threshold may be automatically extracted as ahyper Echoic region. In addition, since the probe 115 is brought intocontact with the body surface, the distance from the treatmentultrasound source 102 to the body surface may be calculated on the basisof the protrusion amount of the probe 115 from the treatment ultrasoundsource 102. Alternatively, an irradiation condition may be set as adefault by designation of a treatment depth or automatic detection aloneon the basis of the general anatomical position relationship between theapplicator and the contact position.

[0102]FIGS. 6A and 6B are characteristic graphs based on which anappropriate irradiation condition is set. FIG. 6A shows the appropriaterange of optimization indexes associated with a focus. FIG. 6B shows theappropriate range of optimization indexes associated with a bodysurface. In this embodiment, to determine an irradiation condition(driving electric power and irradiation period), a focus intensity andirradiation period are determined by using optimization indexes, and thefocus intensity is converted into a driving electric power on the basisof an ultrasound attenuation coefficient and the like.

[0103] Irradiation condition setting operation will be described indetail below with reference to FIGS. 6A, 6B, and 7. Referring to FIG.6A, E_(MAX)-CURVE (FOCUS) indicates the upper limit value ofoptimization indexes; and E_(MIN) -CURVE (FOCUS), the lower limit valueof the optimization indexes. That is, no cell destruction occurs in atumor and appropriate degeneration occurs as long as the optimizationindex falls within the range of E_(MAX)-CURVE (FOCUS) to E_(MIN)-CURVE(FOCUS). Referring to FIG. 6B, E_(MAX)-CURVE (SURFACE) indicates theupper limit value of the optimization indexes within which the bodysurface is not damaged.

[0104] First of all, the operator sets a driving electric power andirradiation period. When, for example, a driving electric power is setby the operator, the system controller 109 calculates an ultrasoundintensity (focus intensity) I_(F1) at the focus corresponding to thedriving electric power and ultrasound intensity (body surface intensity)I_(S1) on the basis of the distance between the tumor (focus) 107 andthe body surface (hyper Echoic region) and an attenuation coefficient(step T1).

[0105] The system controller 109 refers to the characteristic graph ofFIG. 6A on the basis of the focus intensity I_(F1). With this operation,an upper limit Δt_(MAX(FOCUS)) of an irradiation period within which nocell destruction occurs in a tumor and a lower limit Δt_(MIN(FOCUS)) ofan irradiation period within which non-degeneration of the tumor doesnot occur are specified (step T2). In addition, the system controller109 refers to the characteristic graph of FIG. 6B on the basis of thebody surface intensity I_(S1). With this operation, an upper limitΔt_(MAX(SURFACE)) of an irradiation period within which the body surfaceis not damaged is specified (step T2).

[0106] An appropriate irradiation period range in which the tumorappropriately degenerates and the body surface is not damaged isdetermined within the range of Δt_(MIN(FOCUS)) to Δt_(MAX(SURFACE)) fromΔt_(MAX(FOCUS)), Δt_(MIN(FOCUS)), and Δt_(MAX(SURFACE)) (step T3).

[0107] When the appropriate irradiation period range is determined inthis manner, a characteristic curve associated with the focus and acharacteristic curve associated with the body surface are linked to eachother and graphically displayed, as shown in FIGS. 8A and 8B (step T4).Finally, the operator sets an irradiation period Δt_(set) within thisappropriate range.

[0108] According to the above description, a driving electric power isset first, and then an appropriate irradiation period rangecorresponding to the driving electric power is obtained. However, anirradiation period may be set first, and then an appropriate focusintensity range corresponding to the irradiation period may be obtained.The procedure for obtaining this appropriate driving electric powerrange is the same as that for obtaining an appropriate irradiationperiod range. In this case, as shown in FIG. 8C, a characteristic curveassociated with the focus and a characteristic curve associated with thebody surface are linked to each other and graphically displayed, andhence the operator sets a focus intensity within this appropriate range.

[0109] Although any value may be set in irradiation setting, an upperlimit value is used to ensure the maximum degeneration amount at onepoint. If this setting plan is determined in advance, a driving electricpower and irradiation period can be automatically determined. The waveform generating circuit 112 is driven on the basis of this determinationto generate strong ultrasound from the applicator 101.

[0110] In practice, irradiation of ultrasound is often intermittentlyrepeated. Since the temperature of the body surface decreases inirradiation intervals, the appropriate index associated with the bodysurface varies depending on the length of this interval (FIG. 6B).

[0111] The correlation between I_(F1) and I_(S1) can be obtained bygiving to a predetermined function parameters such as the focusingdegree and resonance frequency of the treatment ultrasound source 102,the distance between the focus and the body surface, and attenuation.This function is stored in the memory 111 in advance, and the systemcontroller 109 calculates the correlation on the basis of theparameters.

[0112] An appropriate range of focus intensities or irradiation periodsis obtained in the above manner (step V1 in FIG. 9). Treatmentultrasound is then generated under an irradiation condition set withinthis range to execute medical treatment (step V2). Thereafter, theoperator checks the state of the tumor, and completes or re-executes themedical treatment or re-sets an irradiation condition, as needed (stepV3).

[0113] According to the above description, an appropriate range of focusintensities or irradiation periods is obtained according to optimizationindexes. However, this appropriate range may be calculated in advanceand stored in the memory 111.

[0114] In addition, an appropriate range is defined by one upper limitvalue and one lower limit value. As shown in FIG. 10, however, an upperlimit value/lower limit value selecting circuit 1100 may be connected tothe system controller 109 to selectively use one upper limit value 1101and a plurality of lower limit values 1102 a, 1102 b, and 1102 c througha switch 103.

[0115] (Third Embodiment)

[0116]FIG. 11 shows the arrangement of an ultrasound treatment apparatusaccording to the third embodiment of the present invention. Anultrasound source 201 is made of a piezoelectric element having aconcave surface and serving to irradiate a tumor with treatmentultrasound. The treatment ultrasound is brought to a focus F determinedby the curvature of the concave surface.

[0117] An imaging ultrasound probe 202 is placed in the center of theultrasound source 201. An ultrasound imaging apparatus 203 performssignal processing for the ultrasound signal transmitted/received by theultrasound probe 202. The B-mode image obtained by this signalprocessing is displayed.

[0118] The operator always monitors the state of the tumor whilevisually checking the tumor with the B-mode image. When ultrasoundtreatment is to be started in this environment, the operator inputs anirradiation condition to an ultrasound driving circuit 204 through anoperation panel (not shown) of the ultrasound treatment apparatus. Inthis operation, the operator inputs the irradiation period and intensityof treatment ultrasound, irradiation stop cycle, irradiation stopperiod, and the like in accordance with a treatment plan uponpreliminary diagnosis based on the information obtained by the B-modeimage and other diagnosis means. Thereafter, irradiation of ultrasoundis started.

[0119] In determining the irradiation condition for the ultrasoundtreatment apparatus, an irradiation cycle and period are determinedfirst by an irradiation stop period setting means for determining anobservation condition during irradiation. More specifically, for aninternal organ that does not easily move, a relatively long irradiationcycle and relatively long stop interval can be set. Ultrasound may becontinuously irradiated without setting any stop period depending on thetarget portion. In contrast to this, for an internal organ that moves, ashort irradiation period and short stop period can be set. Obviously, afixed cycle and period may be set.

[0120]FIG. 12 shows the arrangement of the ultrasound driving circuit204 in FIG. 11. A wave form generating circuit 241 generates an initialdriving signal in accordance with the irradiation condition set. A stopsignal generating circuit 242 generates stop signals corresponding to anirradiation period, cycle, and stop period of treatment ultrasound. Asignal synthesizer 243 generates a driving signal by synthesizing theinitial driving signal with a stop signal. This driving signal isamplified by an amplifier 244 with an amplification factor correspondingto the irradiation condition. With this operation, a driving signal fordriving the piezoelectric element of the ultrasound source 201 isgenerated.

[0121] (Dual Mode)

[0122]FIG. 13 shows the operation in a dual mode in the thirdembodiment. Treatment ultrasound is intermittently generated in anarbitrary irradiation cycle. An irradiation period, irradiation interval(stop period), and irradiation cycle can be arbitrarily set by theoperator. For example, the irradiation period, irradiation interval(stop period), irradiation cycle, and treatment period are respectivelyset to 0.95 sec, 0.05 sec, 1 sec, and 5.2 sec.

[0123] While such treatment ultrasound is intermittently generated,scanning of a cross-section inside the patient is continuously repeatedwith imaging ultrasound. The time required for one complete scan on thiscross-section, i.e., the frame period, is set to be shorter than theirradiation interval (stop period), 0.05 sec. In contrast to this, theabove irradiation interval (stop period) is set to be longer than theframe period.

[0124] B-mode image is continuously generated by continuously repeatedscanning. When scanning is performed while treatment ultrasound isgenerated, a B-mode image with an excessively high intensity is obtainedowing to high echo of treatment ultrasound. When scanning is performedwhile treatment step S is stopped, no high echo of treatment ultrasoundis present. Therefore, a B-mode image with an appropriate intensity canbe obtained.

[0125] As shown in FIG. 14, continuously generated B-mode image data isplayed as a moving image on the monitor in real time. In the ultrasoundimaging apparatus 203, B-mode image data corresponding to scanningperformed during a stop period of treatment ultrasound is picked up fromthe continuously generated B-mode image data in synchronism withstopping operation of the treatment ultrasound, and is displayed besidethe moving image. This picked-up B-mode image is switched in theirradiation cycle (1 sec). This B-mode image is therefore displayed asan image (referred to as a skip image) at 1 frame per sec, which isneither a moving image nor a still image.

[0126] As described above, a B-mode image obtained during a stop periodof treatment ultrasound has an appropriate intensity, and hence allowsthe operator to observe the tissue form. In contrast to this, a B-modeimage obtained during generation of treatment ultrasound has anexcessively high intensity, and hence looks completely white. This makesit impossible to see the tissue form. That the B-mode image lookscompletely white indicates that the corresponding portion is actuallyirradiated with treatment ultrasound. The operator can therefore checkthe progress of treatment, any focus deviation from the tumor, and thelike with a skip image while checking irradiation of treatmentultrasound with a moving image.

[0127] (Single Mode)

[0128]FIG. 16 shows the operation in a single mode in the thirdembodiment. In the single mode, only one image is displayed, but thisone image allows the operator to observe a tissue form and checkirradiation of treatment ultrasound as in the dual mode. Treatmentultrasound is intermittently generated in an irradiation cycle. Whilesuch treatment ultrasound is intermittently generated, a cross-sectioninside a patient is scanned with imaging ultrasound such that some ofscan periods, e.g., the first half portion of a scan period (type B),the second half portion of a scan period (type C), and the first andsecond half portions of a scan period excluding a central portion (typeA) overlap a generation period of treatment ultrasound in synchronismwith a stop period of treatment ultrasound.

[0129] In this mode as well, an irradiation period,. irradiationinterval (stop period), and irradiation cycle can be arbitrarily set bythe operator. According to type A, the frame period required for onecomplete scan on a cross-section must be longer than a stop period oftreatment ultrasound. In types B and C, such a restriction is notimposed and hence frame periods can be arbitrarily set.

[0130] The B-mode image obtained by this intermittent scanning isdisplayed as a skip image. Since some of frame periods overlap ageneration period of treatment ultrasound, these portions of the B-modeimage which correspond to generation periods of treatment ultrasoundlook completely white, and those portions of the B-mode image whichcorrespond to stop periods of treatment ultrasound are displayed asB-mode forms, as shown in FIGS. 17A, 17B, and 17C. The operator cantherefore check the progress of treatment, any focus deviation from thetumor, and the like with the skip image, while checking irradiation oftreatment ultrasound with the moving image.

[0131] In the single mode, the operator may continuously repeatscanning, as shown in FIG. 18, instead of intermittently performingscanning in synchronism with stop periods of treatment ultrasound, so asto pick up B-mode images in synchronism with stop periods of treatmentultrasound and display only picked-up B-mode images as skip images.

[0132] Treatment ultrasound may be cyclically stopped or may bearbitrarily stopped at arbitrary time points for arbitrary periods inaccordance with the manual operation performed by the operator, as shownin FIG. 15. During stopping operation, therefore, irradiation oftreatment ultrasound is stopped, and a B-mode image showing a tissueform is displayed. If, for example, the target internal organ does notmove much, the operator need not frequently stop treatment ultrasound tofrequently check for any focus deviation from a tumor. In contrast tothis, if the target internal organ moves greatly, the operator mustfrequency stop treatment ultrasound to frequently check for any focusdeviation from the tumor. The manual operation can flexibly cope withsuch states.

[0133] When treatment ultrasound is manually stopped, the stop periodmay become too long to make a tumor appropriately degenerate in thetreatment period. In order to prevent this, a wave form generatingcircuit 411 prolongs the treatment period by a period during which astop signal generating circuit 421 generates a stop signal.

[0134]FIG. 19 shows an ultrasound treatment apparatus having thefunction of supporting a check on the progress of treatment. FIG. 20Ashows the state of a tumor before treatment. FIG. 20B shows the state ofthe tumor after treatment. An ultrasound imaging apparatus 431 extractsthe intensity of a region 71 including the focus F from a B-mode imagecorresponding to a stop period of treatment ultrasound. In general, theecho gradually increases in intensity to increase the intensity. Forexample, the intensity of a region 72 in FIG. 20B increases 10 sec afterthe start of treatment.

[0135] When the maximum value, total value, or average value ofintensities in this region 72 reaches a predetermined threshold, it isdetermined that the tumor has appropriately degenerated, and theultrasound imaging apparatus 431 transmits a driving stop signal to anultrasound driving circuit 402. In accordance with this signal,treatment is completed. This can prevent destruction of morbid tissue.

[0136] Although intensity information is checked on the basis of theprogress of treatment, this check may be made by analyzing the frequencycomponent of an echo and using an index representing the rate of changein this frequency component. Similar control can be performed by usingchanges in echo intensity from a focus region or frequencycharacteristics instead of using a B-mode image. In this case, theultrasound source 201 is used for reception as well as transmission, andweak ultrasound pulses are transmitted from the ultrasound source 201during irradiation stop periods. Alternatively, a tumor is irradiatedwith weak ultrasound from the ultrasound source 201, and echoes from thetumor are received by the ultrasound probe 202. The received signals areanalyzed to generate information that allows the operator to check theprogress of treatment.

[0137] If the tumor is larger than the focus, the focus F must be movedintermittently or continuously, and treatment ultrasound must berepeatedly irradiated in synchronism with the movement of the focus F.In executing this treatment method, the irradiation condition (intensityand irradiation period) for treatment ultrasound must be set carefullyto appropriately cause degeneration of a tumor and prevent degenerationof normal tissue around the tumor. In this embodiment, the irradiationcondition can be optimized. When the focus F is to be continuouslyirradiated with treatment ultrasound, in particular, the index must bechanged in consideration of the overall frequency/energy density.

[0138] As described above, according to this embodiment, the operatorcan appropriately proceed with treatment while checking the progress oftreatment and generation of treatment ultrasound.

[0139] In the plurality of embodiments described above, an ultrasoundtreatment apparatus 1105 may have only a treatment function and imagedisplay function, while an external ultrasound diagnostic apparatus 1102may have an image generating function, as shown in FIG. 21. When a tumorof a patient is to be irradiated with treatment ultrasound, the focus isset on the tumor before irradiation of treatment ultrasound. Inadjusting the focus, the focal position is specified by the B-mode imageobtained by the ultrasound diagnostic apparatus 1102.

[0140] After the focus adjustment, treatment ultrasound is irradiatedfrom an treatment ultrasound source 1110 of the ultrasound treatmentapparatus 1105. At this time, an amplifier 1111 amplifies the wave formsignal generated by a wave form generating circuit 1112 to voltage-drivethe treatment ultrasound source 1110, thereby irradiating treatmentultrasound from the treatment ultrasound source 1110.

[0141] The amplification type is properly selected for the amplifier1111 according to a design intention in accordance with the wave form ofa driving-signal for driving the treatment ultrasound source 1110. Forexample, a general class B amplification circuit may be used. If thesignal to be handled is a high-frequency pulse, an amplification unit ofa switching type using a class D amplification circuit may be used tohandle a large-output pulse signal.

[0142] A system controller 1120 controls the irradiation timing, waveform, amplification factor, irradiation count, and the like of the waveform generating circuit 1112 and amplifier 1111.

[0143] The system controller 1120 also controls the display contentsgenerated by a display unit 1103 and its display timing. The displayunit 1103 causes an image superimposing circuit 1131 to superimposeinformation necessary for treatment (to be referred to as treatmentinformation hereinafter) on the B-mode image captured by an imagecapturing circuit 1133, and displays the superimposed image on an imagedisplay 1104 through a frame memory 1132 and image outputting circuit1134.

[0144] The display unit 1103 is controlled by the system controller 1120in accordance with the input state of a console 1106 and the overallstate of the system. The ultrasound diagnostic apparatus 1102 has atleast the same arrangement as that of a general ultrasound diagnosticapparatus. An imaging probe 1140 is driven by a transmitting/receivingcircuit 1141. The captured image is subjected to necessary imagereconstruction processing in an image generating unit 1143. Theresultant image is then displayed on an image display 1145 such as animage monitor through an image inputting/outputting circuit 1144. At thesame time, the image inputting/outputting circuit 1144 outputs imageinformation outside the apparatus through an RBG output or video output.This information is captured as image information by the image capturingcircuit 1133.

[0145] Recently, an improvement in diagnostic precision is expected bysimultaneously obtaining pieces of diagnostic information based on aplurality of images according to the common medical image standardcalled DICOM (Digital Imaging and Communication in Medicine). Accordingto this common standard, diagnostic images obtained by image diagnosticapparatuses of different types, e.g., a CT image diagnostic apparatus,MRI image diagnostic apparatus, and X-ray imaging apparatus, can behandled as data having the same data format.

[0146] In the ultrasound treatment apparatus according to thisembodiment, for example, if the image capturing circuit 1133 is designedaccording to this DICOM, the B-mode image obtained by the ultrasounddiagnostic apparatus and the diagnostic images obtained by other imagediagnostic apparatuses can be simultaneously displayed on the samemonitor. This allows the operator to compare and examine the images.

[0147] In addition, not only image information but also other datauseful in treatment can be simultaneously displayed on the monitor ofthe ultrasound treatment apparatus according to the present inventionthrough a computer network.

[0148]FIG. 22 is a timing chart of the image capturing rate, displayrate, and irradiation rate of the ultrasound treatment apparatusaccording to this embodiment. While no treatment ultrasound isirradiated (only a B-mode image is displayed), the image superimposingcircuit 1131 superimposes treatment information on the B-mode imageoutput from the image inputting/outputting circuit 1144 of theultrasound diagnostic apparatus 1102, and the image display 1104displays the resultant image. When treatment ultrasound is to beirradiated, the image capturing circuit 1133 of the ultrasounddiagnostic apparatus is kept on.

[0149] The image capturing circuit 1133 captures diagnostic imagescorresponding to an ultrasound diagnostic image capturing rate 1170 inFIG. 22. When only intermittent display is to be performed, the imagecapturing circuit 1133 need not always capture diagnostic images and maycapture images at an image display refreshing rate 1171 or treatmentultrasound irradiation rate 1172.

[0150] Treatment information is superimposed by the image superimposingcircuit 1131. At this time, a treatment ultrasound generator irradiatestreatment ultrasound corresponding to the treatment ultrasoundirradiation rate 1172 from the treatment ultrasound source 1110. Duringirradiation of treatment ultrasound, noise components appear ondiagnostic images, accompanying the irradiation. For this reason, an olddiagnostic image is replaced with a newly captured diagnostic imageduring an OFF period of the treatment ultrasound irradiation rate 1172.That is, the information in the frame memory is replaced with new imageinformation during an ON period of the image display refreshing rate1171 in FIG. 22.

[0151] With this operation, no noise components appear on images uponirradiation of treatment ultrasound, and diagnostic images without anynoise component can always be displayed. In addition, real-timediagnostic images can be displayed during periods other than treatmentperiods.

[0152] The display unit 1103, ultrasound treatment apparatus 1105, andultrasound diagnostic apparatus 1102 are shown as separate blocks inFIG. 21. However, the same effect as that of the present invention canbe obtained even if the display unit 1103 is incorporated in theultrasound treatment apparatus 1105 or ultrasound diagnostic apparatus1102.

[0153] In addition, according to the result obtained by tests conductedon animals by the present inventors, the intensity of echoes from atumor displayed on a B-mode image gradually changes upon irradiation ofultrasound on the tumor. Each time an echo changes, almost completelyuniform degeneration occurs in a focus region. If, therefore, initialchanges in echo level in the process of uniform degeneration aremonitored to stop irradiation, safe, reliable treatment can be realized.However, since initial changes in reflected echo level are very subtle,it is very difficult to determine by only visually checking an image alevel at which a tumor uniformly degenerates.

[0154]FIG. 23A shows an example of image display before irradiation oftreatment ultrasound. FIG. 23B shows an example of image display afterirradiation of treatment ultrasound. In the displayed image in FIG. 23A,a B-mode image 1156, focal position 1150, and focus proximity range 1153are displayed. At the same time, a intensity difference amount shiftgraph 1155 is displayed on a lower portion of the screen. On thisintensity difference amount shift graph 1155, a intensity differenceamount 1151 and threshold curve 1152 are displayed.

[0155] This ultrasound treatment apparatus obtains the differencebetween the average intensity, as an initial value, in the focusproximity range 1153 on the B-mode image 1156 before irradiation oftreatment ultrasound and the average intensity near the focus on theB-mode image 1156 during intermittent irradiation of treatmentultrasound.

[0156] According to a method of obtaining this intensity difference, forexample, a intensity signal corresponding to a reception echo level isextracted from an ultrasound transmitting/receiving circuit (not shown)for constructing the B-mode image 1156 at an ultrasound reception timingcorresponding to the focus proximity range 1153. The average value oflevels of one-frame component of this intensity signal is compared withthe average value of a similar intensity signal that has been obtainedbefore irradiation of treatment ultrasound. The difference between theseaverage values is displayed as the intensity difference amount 1151 onthe intensity difference amount shift graph 1155.

[0157] Note that the one-frame component does not indicate a one-framecomponent based on scanning lines constituting an image on, for example,a TV monitor, but “one frame” is formed when one raster operation at thestart point of scanning is performed at the vibrator at the end point ofscanning, provided that “one raster operation” is transmission/receptionof ultrasound at one of many vibrators of the ultrasound probe which islocated at the start point of scanning. These constructed frames areswitched differently depending on the body tissue under examinationwhose B-mode image is to be obtained, and are properly selected inaccordance with a direction from the operator or apparatus settingsbefore operation.

[0158] If, for example, an internal organ that moves fast, e.g., acirculatory organ, is to be treated, a short transmission/receptionperiod is assigned to one raster to shorten the total time required toconstruct one frame. This makes it possible to increase the number offrames per unit time. Therefore, the apparatus can satisfactorily followthe fast movement of, e.g., a cardiac valve.

[0159]FIG. 23B shows the image display operation of the ultrasoundtreatment apparatus after irradiation of treatment ultrasound. Incontrast to the B-mode image 1156 before irradiation of treatmentultrasound, a hyper Echoic region 1154 is superimposed on the focusproximity range 1153 around the focal position 1150. This hyper Echoicregion 1154 is produced because the tissue of the tumor at the focalposition 1150 becomes degenerated protein. In the ultrasound treatmentapparatus of this embodiment of the present invention, the differencebetween the average value of intensity information of the hyper Echoicregion 1154 and the average value of intensity information beforeirradiation is displayed as the threshold curve 1152.

[0160] More reliable, uniform ultrasound irradiation treatment can berealized by control which stops irradiation of treatment ultrasound whenthe above difference exceeds a predetermined threshold. For example,irradiation of treatment ultrasound is stopped when a change inintensity difference amount indicated by the intensity difference amountshift graph 1155 exceeds the threshold curve 1152. This stop control canbe realized by calculating the difference between captured intensityinformation and a predetermined threshold, and stopping the operation ofa driving circuit (not shown) for generating treatment ultrasound on thebasis of the difference.

[0161] Control may be performed such that irradiation of treatmentultrasound is automatically stopped when a change in intensitydifference amount becomes below the threshold curve 1152. In addition,upper and lower thresholds may be set, and irradiation is stopped whenthe above change falls outside the range of the upper and lowerthresholds. Alternatively, information (guide) of an irradiation stop isgiven to the operator to notify the operator of the end of treatment by,for example, generating a sound, performing display operation (e.g.,blinking characters indicting the completion of irradiation), orvibrating the ultrasound applicator held by the operator with his/herhand.

[0162] Note that a region to be captured to calculate the average valueof intensity information may be designated by a direction input bymanually operating a trackball. Alternatively, this apparatus mayadditionally have the function of automatically setting a size byselecting data from location and range data as default values.

[0163] There are differences in intensity before irradiation oftreatment ultrasound among patients owing to the symptoms, degrees ofsymptoms, and physical constitutions of the respective patients. Toprevent the influences of such differences among individuals, an initialaverage intensity is normalized to a value determined on the basis of,e.g., statistical data and displayed on the screen, together with thethreshold curve 1152. In this display form, intensity change informationresistant to the influence of a difference among individuals can begiven to the operator by displaying the process of changes in theintensity difference amount 1151 over time.

[0164] In the above embodiment, difference information associated withan original image before irradiation of treatment ultrasound isdisplayed on the basis of the information obtained by averagingintensity signals in the focus proximity range 1153 at the focalposition 1150. However, an average intensity signal acquisition regionmay be set at a predetermined fixed position, and a value obtained atthis position may be used. According to still another method, imagescorresponding to a plurality of frames are acquired when intermittentB-mode images are obtained, and intensity signals at the focal position1150 are time-averaged, thereby displaying the resultant value.

[0165] In the ultrasound treatment apparatus of each embodiment of thepresent invention, an ultrasound image diagnostic apparatus is used asan image diagnostic apparatus. However, the present invention is notlimited to this, and can be applied to the display/control operations ofother image diagnostic apparatuses such as a CT apparatus, X-rayapparatus, and MRI apparatus.

[0166]FIG. 24 shows one example of a displayed image 1160, which isdisplayed on the monitor (not shown) of the ultrasound treatmentapparatus according to the present invention. On this display image1160, B-mode images of a tumor, which are captured by the ultrasoundimage diagnostic apparatus in time series are displayed. This displayoperation is performed to simultaneously display an initial B-mode image1161, first process image 1162 obtained period t=P sec after irradiationof treatment ultrasound, second process image 1163 obtained t=Q secafter irradiation, third process image 1164 obtained t=R sec afterirradiation, and latest B-mode image 1165.

[0167] The initial B-mode image 1161 is a B-mode image beforeirradiation of treatment ultrasound on a tumor. Time-series images,fromthis initial image to the latest B-mode image 1165 as the current imageare simultaneously displayed. As the tumor is irradiated with treatmentultrasound, the temperature of the focus portion rises, and the focusportion becomes degenerated protein. As a consequence, this portionbecomes the hyper Echoic region 1154. This hyper Echoic region 1154expands as an irradiation period elapses. For example, as shown in FIG.24, the hyper Echoic region 1154 gradually expands in time series. fromthe first process image 1162 to the latest B-mode image 1165.

[0168] By displaying a trend in image changes due to degeneration intime series, the progress of ultrasound treatment or its completiontiming are clearly displayed for review by the operator. If, forexample, a plurality of images are displayed with respect to an initialimage, as shown in FIG. 24, while images other than the initial imageare updated over time, the operator can grasp a trend in changes at aglance.

[0169] Note that the respective captured B-mode images can be displayedat predetermined time intervals. Alternatively, the elapsed time fromthe start of irradiation of treatment ultrasound to the current time maybe divided into elapsed times at predetermined intervals, and therespective captured B-mode images can be displayed at the respectiveelapsed times.

[0170] In addition, the normal B-mode image display and image display ofB-mode images captured in time series may be switched at arbitrary orpredetermined time intervals. In this embodiment, B-mode images aredisplayed only in time series. However, instead of the image displayshown in FIGS. 23A and 23B, a B-mode image during treatment and an imagebefore irradiation of treatment ultrasound can be selectively displayed.

[0171] Each embodiment described above has exemplified the ultrasoundtreatment apparatus of focusing type. However, the effects unique to thepresent invention can be obtained even if the present invention isapplied to an ultrasound treatment apparatus of a type other than thefocusing type. In addition, the type of generating treatment ultrasoundis not limited to the type of using vibrators having concave surfaces.For example, the same effect can be obtained by using a two-dimensionalarray of vibrators in the form of a flat plate. Alternatively, anelectromagnetic induction type ultrasound source may be used.

[0172] In each embodiment described above, medical treatment of a tumorby using the thermal effect of ultrasound has been described as anexample. However, similar effects can be obtained by applying thepresent invention to medical treatment of other target portions toobtain a dynamic effect or chemical effect;

[0173] Additional advantages and modifications will readily occur tothose skilled in the art. Therefore, the invention in its broaderaspects is not limited to the specific details and representativeembodiments shown and described herein. Accordingly, variousmodifications may be made without departing from the spirit or scope ofthe general inventive concept as defined by the appended claims andtheir equivalents.

What is claimed is:
 1. An ultrasound treatment apparatus comprising: anultrasound source for generating treatment ultrasound which is focused;a driving circuit for driving said ultrasound source to generatetreatment ultrasound from said ultrasound source; and a controller forcontrolling said driving circuit to cause said driving circuit to drivesaid ultrasound source under an irradiation condition in which anoptimization index obtained by a product of a focus intensity (W/cm²) ofthe treatment ultrasound, an irradiation period (sec) of the treatmentultrasound, and a frequency (MHz) of the treatment ultrasound fallswithin an appropriate range from 6,000 (inclusive) to 40,000(inclusive).
 2. An apparatus according to claim 1, wherein saidcontroller controls said driving circuit to cause said driving circuitto drive said ultrasound source under an irradiation condition in whichthe focus intensity becomes not more than 2,000 (W/cm²).
 3. An apparatusaccording to claim 1, further comprising a console for inputting atleast one of the focus intensity and the irradiation period, saidcontroller determining the other of the focus intensity and theirradiation period on the basis of the input one of the focus intensityand the irradiation period and a frequency of the treatment ultrasoundsuch that the optimization index falls within the appropriate range. 4.An apparatus according to claim 1, further comprising a console forinputting both the focus intensity and the irradiation period, and meansfor generating a warning when an optimization index obtained from theinput focus intensity, the input irradiation time, and a frequency ofthe treatment ultrasound falls outside the appropriate range.
 5. Anapparatus according to claim 1, further comprising a memory storing anappropriate range of the optimization index for each internal organ. 6.An apparatus according to claim 1, further comprising display means forgraphically displaying the optimization range.
 7. An ultrasoundtreatment apparatus comprising: an ultrasound source for generatingtreatment ultrasound which is focused; a driving circuit for drivingsaid ultrasound source to generate treatment ultrasound from saidultrasound source; and a controller for determining an irradiationcondition on the basis of an optimization index obtained from a productof a focus intensity (W/cm²) of the treatment ultrasound, an irradiationperiod (sec) of the treatment ultrasound, and a frequency (MHz) of thetreatment ultrasound, and controlling said driving circuit to cause saiddriving circuit to drive said ultrasound source under the determinedirradiation condition.
 8. An ultrasound treatment apparatus comprising:an ultrasound source for generating treatment ultrasound which isfocused; a driving circuit for driving said ultrasound source togenerate treatment ultrasound from said ultrasound source; and acontroller for determining an irradiation condition on the basis of afocus intensity of the treatment ultrasound and an ultrasound intensityin at least one hyper Echoic region including a body surface of apatient between said ultrasound source and the focus, and controllingsaid driving circuit to cause said driving circuit to drive saidultrasound source under the determined irradiation condition.
 9. Anapparatus according to claim 8, wherein said controller determines acomprehensive appropriate range on the basis of an appropriate range ofa product of a focus intensity (W/cm²) of the treatment ultrasound, anirradiation period (sec) of the treatment ultrasound, and a frequency(MHz) of the treatment ultrasound, and an upper limit of a product of anultrasound intensity (W/cm²) in the hyper Echoic region, the irradiationperiod (sec), and the frequency (MHz) of the treatment ultrasound. 10.An apparatus according to claim 9, further comprising display means forgraphically displaying the appropriate range, the upper limit, and thecomprehensive appropriate range.
 11. An apparatus according to claim 9,further comprising a memory storing the appropriate range and the upperlimit for each internal organ.
 12. An apparatus according to claim 8,further comprising means for automatically extracting the hyper Echoicregion from B-mode image data associated with a cross-section includinga focus of the treatment ultrasound.
 13. An ultrasound treatmentapparatus comprising: an ultrasound source for generating treatmentultrasound which is focused; a driving circuit for driving saidultrasound source so as to alternately generate the treatment ultrasoundand stop the treatment ultrasound; an imaging ultrasound probe; meansfor continuously scanning a cross-section including the focus of thetreatment ultrasound with imaging ultrasound through said imagingultrasound probe so as to sequentially generate B-mode image data; andmeans for displaying the B-mode image data as a moving image and alsodisplaying B-mode image data picked up in synchronism with stop periodsof the treatment ultrasound.
 14. An apparatus according to claim 13,wherein a stop period of the treatment step is set to be longer than atime required to scan the cross-section.
 15. An apparatus according toclaim 13, further comprising means for arbitrarily setting at least oneof a generation period of the treatment ultrasound and a stop period ofthe treatment ultrasound.
 16. An apparatus according to claim 13,wherein said driving circuit adjusts an intensity of the treatmentultrasound in accordance with a stop period of the treatment ultrasound.17. An apparatus according to claim 13, further comprising means formeasuring a progress of treatment of a tumor on the basis of a focusintensity of B-mode image data captured in synchronism with a stopperiod of the treatment ultrasound.
 18. An apparatus according to claim17, wherein said driving circuit comprises means for adjusting ageneration period of the treatment ultrasound and/or a stop period ofthe treatment ultrasound on the basis of the measured progress oftreatment.
 19. An apparatus according to claim 13, further comprisingmeans for displaying the picked-up B-mode image data in a list form. 20.An ultrasound treatment apparatus comprising: an ultrasound source forgenerating treatment ultrasound which is focused; a driving circuit fordriving said ultrasound source so as to alternately generate thetreatment ultrasound and stop the treatment ultrasound; an imagingultrasound probe; means for intermittently executing scanning operationof scanning a cross-section including a focus of the treatmentultrasound with image ultrasound through said imaging ultrasound probeso as to intermittently generate B-mode image data, periods of thescanning operation partly overlapping generation periods of thetreatment ultrasound; and means for displaying the B-mode image data asa skip image.
 21. An apparatus according to claim 20, wherein a firsthalf portion of the scanning operation overlaps a generation period ofthe treatment ultrasound.
 22. An apparatus according to claim 20,wherein a second half portion of the scanning operation overlaps ageneration period of the treatment ultrasound.
 23. An apparatusaccording to claim 20, wherein the first and second halves of thescanning operation excluding a central portion overlap a generationperiod of the treatment ultrasound.
 24. An apparatus according to claim20, further comprising means for displaying the B-mode image in a listform.
 25. An ultrasound treatment apparatus comprising: an ultrasoundsource for generating treatment ultrasound which is focused; a drivingcircuit for driving said ultrasound source so as to alternately generatethe treatment ultrasound and stop the treatment ultrasound; an imagingultrasound probe; means for continuously executing scanning operation ofcontinuously scanning a cross-section including the focus of thetreatment ultrasound with imaging ultrasound through said imagingultrasound probe so as to sequentially generate B-mode image data; meansfor picking up B-mode image data from the B-mode image data such thatperiods of the scanning operation partly overlap generation periods ofthe treatment ultrasound; and means for displaying the picked-up B-modeimage as a skip image.
 26. An ultrasound treatment apparatus comprising:an ultrasound source for generating treatment ultrasound which isfocused; a driving circuit for driving said ultrasound source so as toalternately generate the treatment ultrasound and stop the treatmentultrasound; means for continuously inputting B-mode image dataassociated with a cross-section including a focus of the treatmentultrasound; means for picking up B-mode image data corresponding to astop period of the treatment ultrasound from the B-mode image data; andmeans for displaying the picked-up B-mode image data as a skip image.27. An apparatus according to claim 26, further comprising means fordisplaying the picked-up B-mode image data in a list form.
 28. Anultrasound treatment apparatus comprising: an ultrasound source forgenerating treatment ultrasound which is focused; a driving circuit fordriving said ultrasound source to generate the treatment ultrasound;means for continuously inputting B-mode image data associated with across-section including a focus of the treatment ultrasound; means forpicking up the focus intensity from the B-mode image data; and means fordisplaying the picked-up intensity as changes over time.
 29. Anapparatus according to claim 28, further comprising means for spatiallyaveraging the picked-up intensities.
 30. An apparatus according to claim28, further comprising means for measuring a change amount from aninitial value of the picked-up intensities, and means for stoppinggeneration of the treatment ultrasound or decreasing an intensity of thetreatment ultrasound when the change amount exceeds a predeterminedthreshold.
 31. An apparatus according to claim 28, further comprisingmeans for measuring a change amount from an initial value of thepicked-up intensities, and means for generating a warning when thechange amount exceeds a predetermined threshold.